1. Field of the Invention
The present invention relates to a lithium battery, particularly to a high temperature-proof device for a lithium battery.
2. Description of the Related Art
Although lithium batteries have advantages of high energy conversion efficiency, long service life and superior stability, the content thereof is likely to be denatured by weathering, dramatic temperature variation, or collision. The denatured content may cause the internal temperature to rise or even cause explosion. Therefore, the designers of lithium batteries must take much care in safety problems.
Refer to FIG. 1 and FIG. 2 for a conventional safety device of a lithium battery. In the prior, a pressure relief device 50 is installed on one face of a lithium battery 52. A sealing board 54 is arranged on the same face of the lithium battery 52. The sealing board 54 has at least one through-hole 56 where a pressure relief module 58 is arranged. The pressure relief module 58 comprises a top cover 60. The top cover 60 has at least one exhaust hole 62 at two ends thereof. An engagement member 64 is secured inside the top cover 60. A pressure relief valve 66 is arranged inside the engagement member 64. The pressure relief valve 66 has an annular trench 68. The pressure the annular trench 68 can withstand is smaller than that the surrounding material can do. Once the pressure of the lithium battery 52 exceeds a specified value, the annular trench 68 will break firstly. Thus is detached the pressure relief valve 66 and released the pressure. The prior art can indeed prevent from too high a pressure inside a lithium battery. However, the prior art cannot prevent a lithium battery from explosion caused by too high a temperature.
Accordingly, the present invention proposes a high temperature-proof device for a lithium battery to overcome the abovementioned problem.